Now compare that to the PSTN: what does 555-123-4567 really tell you? Not much. It’s just a string of digits with no inherent context. And unlike email, I can’t even choose to outright refuse delivery of a call at the network level.
Now compare that to the PSTN: what does 555-123-4567 really tell you? Not much. It’s just a string of digits with no inherent context. And unlike email, I can’t even choose to outright refuse delivery of a call at the network level.
It tells you exactly as much as the "from" field does in your email.
> you have more tools to work with in email.
Only if you're an engineer implementing a mail server configuration. But if you're implementing a telco you also have more tools to work with than a caller ID.
End users use DMARC/SPF the same way end users use STIR/SHAKEN... they don't. None of them are user-servicable values. And service providers use DMARC/SPF the same way end users use STIR/SHAKEN... they implement those controls for their users in the form of a managed service.
Email gives end users multiple signals and filters to work with. PSTN doesn't, and that's why I disagree with your equivalence.
You can take advantage of it because you're an expert. Just because email vomits out more information that are useful for experts doesn't mean it is better as a real world system for normal people who use it.
At that point, we’re repeating the same values clash — you see regulation as a workable fix, I see it as evidence of fragility. I don’t think continuing this line is going to get us any further.